Consolidated Statement of Shareholder's Interest - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Shareholder's Interest [Roll Forward]
Balance at beginning of period		$ 13,389			$ 13,389
Net income	$ 255	234	$ 286	$ 240	489	$ 526
Balance at end of period	13,554				13,554
Shareholder's Interest [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	5,166		5,166	5,166		5,166
Net income	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax	0	0		0
Distributions declared	0	0	0	0
Stockholders' Equity, Other			0
Balance at end of period	5,166	5,166	5,166	5,166	5,166	5,166
Accumulated Other Comprehensive Income/(Loss) (Note11) [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	(949)		(929)	(1,017)		(1,017)
Net income	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax	(54)	(120)	18	88
Distributions declared	0	0		0
Stockholders' Equity, Other			0
Balance at end of period	(1,003)	(949)	(911)	(929)	(1,003)	(911)
Retained Earnings [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	9,286		7,968	7,728		7,728
Other Comprehensive Income (Loss), Net of Tax	0	0	0	0
Distributions declared	(150)	0	0	0
Balance at end of period	9,391	9,286	8,254	7,968	9,391	8,254
Parent [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	13,503
Net income	255	234	286	240
Other Comprehensive Income (Loss), Net of Tax	(54)	(120)	18	88
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance			12,205	11,877		11,877
Distributions declared	(150)	0		0
Stockholders' Equity, Other			0
Balance at end of period	$ 13,554	$ 13,503			$ 13,554
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance			$ 12,509	$ 12,205		$ 12,509